code: def test_sankey():
      # lets just create a sankey instance and check the code runs
      sankey = Sankey()
      sankey.add()
  
file_path: matplotlib/lib/matplotlib/tests/test_sankey.py
imports: import pytest
  from numpy.testing import assert_allclose, assert_array_equal
  from matplotlib.sankey import Sankey
  from matplotlib.testing.decorators import check_figures_equal
label_desc: Use image node_id 1 for calling a global function with example usage: test_sankey() without return types